Machinable alloy

ABSTRACT

A FREELY MACHINABLE ALLOY COMPRISING, AS EXPRESSED IN PERCENT BY WEIGHT:   NICKEL: 50.0%-52.0% SELENIUM: 0.1%-0.4% MANGANESE: 0.5%-2.0% IRON: BALANCE

cordance with the different r.p.m. and feed rates set 3,623,864 forth in Table I below: MAfiHENAlBLE ALLOY TABLE I George A. Maiesko, Glen Ridge, NJL, assignor to Willanr B. Driver Qornpany 5 t 1 Feed rate, Surface, N Drawing. Filed APT. 9 1970, Ser- No. 28,045 lame 01 in 1110 res r.p.m. inches/rev. feet/minute lint. Cl. C222 19/00 530 .002; 5g 0 7 US. Cl. 75 170 3 Claims 510 88 93 665 .0042 113 867 .0042 142 l'ii 333 iii I i9 0 ABSTRACT OF 1H2 DlsCLOSURE 1,600 99 3 8 A freely machinable alloy comprising, as expressed in {288 138 o 1,600 .0135 100 pcrcent by wei ht. P 55 7 Nickel: 50.0% 52.0% 11383 13 8 is; Selenium: 0.l%0.4% 1,600 0 15 1, 384 47 Manganese: 0.5%2.0% 600 0 1 Iron: Balance; For constant depth of cut (.025") and feed rate i (.0042 inches/rev.) the selenium-containing alloys could CROSS REFERENCE To RELATED be turned on a lathe at 241 surface feet per minute with APPL 1c ATIONS no undesirable effects. The work piece remained cool. The selenium free alloys became very hot at 72 surface In c0-pending patent application S.N. 873,508, filed feet per minute and the machining lubricant began to Nov. 3, 1969, selenium additions to different alloys, smoke n surface feet per minute causing a sharp namely iron-nickel-cobalt alloys, are disclosed by the detenoranon of the Surface finlshsame inventor and assigned to the same assignee as the At a Constant of 1600 and a depth of cut of .025", the selenium containing alloys could be fed in a trouble free manner at rates ranging from .0042 to .0384 inches/rev. Under the same conditions the selepresent application. The alloys contemplated herein are nickel-iron-alloys.

SUMMARY OF THE INVENTION, nium-free alloys ruined the tool when the feed rate was increased beyond .0060 inches/rev.

Certain alloys of the nickel-iron p are used in I found that when the selenium content was reduced ing seals between metals and glass or metals and cerambelow about .l% and the manganese content was reics as well as in other applications wherein the thermal duced simultaneously below 0.5%, the machinability coeificients of expansion and other properties are critical. characteristics were not substantially improved as com- The e alloy ar chafacteyizgd b h d i bl pared to known alloys. When the selenium content was property of poor machinability. As a result, tools used increased about 04% and the manganese cohtfiht in shaping such alloys wear much too rapidly, even when ihcfeased slmullahgousll above the machlflablhty the machining is carried out at relatively low speeds and charactenstic s were not degraded but the thermal expan' feed rates. sion propertles of the alloys began to vary beyond the ranges specified and required. As long as the selenium and manganese additions are maintained Within the ranges set forth herein, any increase of selenium content must be accompanied by an increase (not necessarily a proportional increase) in the manganese content I have discovered that the addition of selenium in amounts falling wthin the range 0.1% to 0.4% (by weight) coupled with the simultaneous addition of manganese in amounts falling within the range 0.5%-2.0% to a nickel-iron alloy comprising %52% nickel, balto maintain forgeabflity ance iron, results in alloys with sharply enhanced ma- What is claimed is: chinability at the same time with Otherwise l. A freely machinable alloy consisting essentially of, stantially unchanged physical and mechanical properties. 50 as expressed in percent b i As a result, excesslve tool weal no longer takes place. Nickel: 50.0% 520% DETAILED DESCRIPTION OF PREFERRED Selenium: 0.l%0.4%

MB DI Manganese: 0.5%-2.0%

Iron: Balance A first plurality of alloys were fabricated with com- 55 positions falling Within the ranges Set below: 2. An alloy as set forth in claim 1 wherein any increase of selenium content within 0.l%0.4% must be Nickel: accompanied by an increase of manganese content with- Selenium: in the range of 0.5%-2.0%. Manganese 0.5 %2.0% (10 3. An alloy as set forth in claim 2 containing less than a Minor elements (Simon, carbon, etc): 1% 1%; of minor elements such as s1l1con and carbon.

Iron: Balance References Cited A second plurality of alloys without selenium and UNITED STATES PATENTS with a manganese content of less than 0.5% but other- 2,471,079 5/1949 Post et wise of like composition to the first plurality were fabri- 3,138,454 6/1964 Williams cated in the same manner.

Both sets of alloys were tested for machinability in ac- RICHARD O. DEAN, Primary Examiner 

